Limitations of the piezoelectric array technologies conventionally used for ultrasonics inspired researchers to explore an alternative mechanism for generating ultrasound via light (the photoacoustic effect). Coupling this with 3-D printing, the group was able to generate sounds fields with specific shapes for potential use in biological cell manipulation and drug delivery. As the group reports in this week’s Applied Physics Letters, their work focuses on using the photoacoustic effect to control ultrasound fields in 3-D.